1. Field of the Invention
The present invention is related to a bore scope that is inserted, for example, into the bore hole of an engine cylinder in order to observe the interior without removing the cylinder head.
2. Description of Related Art
When inspecting the interior of engine cylinders at an automobile equipping plant, etc., a bore scope is used to inspect the interior without going to all the trouble to remove the cylinder head.
As indicated in FIG. 6, objective lens 31 is arranged on one end, and lenses 35 are arranged coaxially in a series at specified distances within rigid barrel 34, on the other end of which is mounted eyepiece 33 that provides ocular lens 32.
Then, when this objective lens 31 side of barrel 34 is brought near the observation area, the light image, which is incident through objective lens 31, can be observed on the eyepiece 33 side.
However, because this linked lens system arranges multiple lenses 31, 32, 35, 35 coaxially in a series, it is difficult to bring out light axis precision, and there is the problem that a clear image cannot be obtained if there is the slightest light axis discrepancy.
Also, when attempting to illuminate the object to be observed, there is the problem that, because rehalation occurs in which light is randomly reflected within barrel 33 when the illumination light passes through the inside of the barrel and is made incident upon the object to be observed, a separate light bulb must be provided, for example, on the end peripheral surface of barrel 33 so that the object to be observed can be illuminated from the outside of the barrel, and thus the end becomes large scale.
Furthermore, there is also the conventional example in FIG. 7. Objective lens 42 is arranged on the end of image guide 41 which consists of bundled fibers, and fiberscope 40, on which is mounted eyepiece 45 that provides ocular lens 43 on the other side of image guide 41, does not have light axis discrepancies because objective lens 42 and ocular lens 43 are arranged on the two ends of image guide 41. Moreover, because the light exit end 44a of light guide 44 is arranged in a ring-shape on the periphery of objective lens 42, when this is applied to the bore scope, the illumination light can illuminate the object to be observed without making the end large scale.
Nonetheless, there is the problem that, because the light which exits from ring-shaped light exit end part 44a of light guide 44 is dispersed to outside the range which image guide 41 can observe, the light utilization efficiency is poor, with the amount of light incident on the object to be observed being a scant 20-30% of the total amount of light exiting from light guide 44.
Also, light exit end part 44a of light guide 44 is arranged on the periphery of objective lens 42 and is exposed at the end surface, and if the end of image scope 40 becomes dirty with oil, etc. when, for example, observing the interior of an engine cylinder, the oil adhering to the lens surface of objective lens 42 can be wiped off relatively easily because that surface is smoothly curved, but because the light exit end part 44a of light guide 44 is arranged on the periphery of objective lens 44 in a ring-shape that exposes the ends of multiple optical fibers, the oil adhering to light exit end part 44a can not be wiped off cleanly, and consequently, there is the problem that there is great light loss.
Of course, if light exit end part 44a of light guide 44 is arranged inside of objective lens 42, there is no such problem because light exit end part 44a is protected by objective lens 42, but in that case, as indicated in FIG. 8, the illumination light is incident in a ringshape that surrounds the outside of observation range W, and it is not possible to illuminate the object to be observed efficiently at the area to be brought into focus.
Thus, the present invention improves the light utilization efficiency by making the light fall in a manner concentrated on the area to be observed, and, at the same time, addresses the technical issue of making it easy to wipe off the tip even when it is dirtied by oil, etc.